Some surgical procedures require the compression, e.g., clamping, of a patient's tissue. Such procedures may include, e.g., anastomosing, stapling, and resecting of tissue. For example, where cancerous tissue is identified in a patient's gastrointestinal tract, the cancerous tissue may need to be surgically removed. Where, for example, the cancerous tissue is located on the colon and is accessible by surgical instrumentation, the surgeon may make an incision in the patient's abdomen to allow access to the bowel. The surgeon may then use a linear cutting and stapling device, such as that described in U.S. Patent Application Publication No. 2009/0101692, which is expressly incorporated herein in its entirety by reference thereto, to cut and staple the colon tissue on opposite sides of the cancerous portion to be removed. In this procedure, the colon is externally clamped (e.g., between opposed jaws) to compress the tissue. While the tissue is compressed, a cutter and a stapler are activated to make a linear cut and apply typically two linear rows of staples in the areas adjacent the cut.
The stapling thus closes both open ends of the portion of the bowel to be removed, as well as providing a temporary closure of the two cut ends of the bowel. This closure limits exposure of the surrounding tissue to the interior of the bowel, thus limiting the risk of infection.
After the cutting and stapling procedure, the cancerous portion of tissue may be removed from the patient's body.
To achieve effective stapling, e.g., in the above procedures, the tissue must be compressed to the extent that there is an adequately small tissue gap, e.g., one millimeter, between the faces of the tool. During this compression, the mechanical components of the clamping mechanism of the cutting and stapling device may be subjected to a high level of force or strain. Where, e.g., the jaws are closed by rotation of one or both of the jaws about a proximally located pin, the pin and/or the adjacent structures of the jaws in communication with the pin bear a substantial load, which may lead to deformation. Where the pin passes through a through hole in one or both of the jaws, deformation may be more likely due to the weakening of the jaw structure resulting from the through holes.
Further, proximally extending structures of the jaws, e.g., an anvil, may deform, including, e.g., splaying laterally outwardly. The likelihood of deformation may also be increased by the removal of material for through slots, e.g., in a pin-and-slot type actuation arrangement.
This deformation may lead to, e.g., misalignment between the jaws and/or failure of the clamping mechanism. Where one of the jaws is configured as an anvil and the other jaw is configured to drive staples, e.g., from a staple cartridge, into the anvil, misalignment of the jaws may cause misalignment of the anvil and staple pockets. This may cause the staples to be improperly formed, which may increase the risk of sepsis and other potentially dangerous complications.
Thus, it is desirable to provide a clamping mechanism that substantially reduces the likelihood of deformation in the jaws.